The 31st Annual Symposium on the Biology of Skin will address the topic "Structural Elements of the Dermis." This subject will deal with the bricks and mortar of cutaneous structure and to which is attached and intercalated the epithelium, adnexal structures, and vascular channels as well as the resident populations of dermal cells. The scope of the meeting will encompass analysis of the genetic material which gives rise to certain collagen protein macromolecules, such as the alpha2-chain gene, as well as the genes coding for elastin. The biochemical heterogeneity of the collagens will be reviewed and their biomechanical properties, at least as a tissue, will be described. The interactions of collagens with fibronectin and other attachment proteins represent a new frontier in protein-protein interactions as well as cell-protein connections. The cellular regulation of collagen synthesis as a normal process and an abnormal process in disease will be discussed. Aberrations of collagen synthesis in scleroderma, osteogenesis imperfecta, the dermolytic bullous dermatoses and Ehlers Danlos diseases will be compared at the molecular level. Elastin formation, assembly and degradation, control of elastin synthesis and mechanical properties of elastin will be presented. Finally, proteoglycan structure, function and chemical composition will be described, both as it occurs in the normal state and in proteoglycan storage diseases. Regional modulation of fibroblast function, particularly as it affects proteoglycan synthesis, will focus on select diseases in man.